Method and equipment for detecting pattern defect

Inspection apparatus and method in which laser source emits a laser beam and a coherence of the laser beam emitted from the laser source is reduced by a coherence reducer. A detector detects light from the sample irradiated with the coherence reduced laser beam and a processor processes a signal outputted from the detector and detects a defect on the sample. The coherence reducer has an optical path which includes a plurality of at least one of optical fibers and glass rods.